(1) Field of the Invention
The present invention relates to control apparatus and method for a hybrid vehicle which control a line pressure regulator valve, the line pressure regulator valve regulating a line pressure of a hybrid (vehicle) drive train.
(2) Description of Related Art
A Japanese Patent Application First Publication No. 2010-179860 published on Aug. 19, 2010 exemplifies a previously proposed control apparatus for a hybrid vehicle. In details, in the hybrid vehicle, connections are made in such a sequence as an engine, a first clutch, a motor/generator, a transmission, and driving wheels to constitute the hybrid drive train. The first clutch is a hydraulic pressure clutch whose engagement and release (open) are controlled in response to a hydraulic pressure of a working oil and the transmission is gear shift controlled in response to the working oil hydraulic pressure. In such a hybrid vehicle as described above, a required hydraulic pressure supply is basically carried out using a mechanical oil pump (hereinafter, abbreviated as mecha O/P) actuated through a motor shaft. In addition, when a discharge pressure from the mecha O/P becomes insufficient during an EV mode in which the vehicle is traveling, with only the motor/generator as a driving source, or during a vehicle stop, the hydraulic pressure supply is carried out using an electrically driven oil pump (hereinafter, abbreviated as an electrically driven O/P) actuated by mans of a sub motor. It should, herein, be noted that electrically driven O/P is controlled using a torque control method in which the discharge pressure from electrically driven O/P is controlled by means of a specified hydraulic pressure (torque). It is possible to use the discharge pressure from electrically driven O/P without waste by adopting the torque control method.